The project focuses on intracellular events in the replication of influenza virus. Specifically, we are concerned with three questons: (1) Are 8 segments of RNA which make up the genome of the virus transcribed, translated, and replicated independently or are they processed as one unit. UV irradiation of infected cells followed characterization of the viral mRNAs indicated that each segment carried its own promoter region and that there was no evidence for linkage. (2) What is the nature of the von Magnus or incompleted influenza virus (IIV) genome? RNA extracted from various serial high multiplicity passages of IIV showed that the three largest RNA segments were lost first with segment 1, the largest, being the first to be affected. Similarly, both types of complementary RNAs found in infected cells, the complementary template and the mRNAs also showed segments 1, 2, and 3 to be the first lost. (3) Currently, we have begun experiments to determine if there are temporal controls on virus RNA synthesis. We are examining the molar ratios of each of the segments of both types of complementary RNAs relative to each other as a function of time after infection. These experiments should enable us to determine whether certain segments are synthesized early and others late in infection.